Subframe for vehicle

Abstract

In a vehicle subframe 1, a pair of side members 110 and 130 includes upper side members 111 and 131 and lower side members 117 and 137, respectively, the lower side members 117 and 137 extending opposed on a downward side to the upper side members 111 and 131 while being elongated to a rearward side, and a pair of mounting members 60 and 80 is joined respectively to the lower side members 117 and 137 of the pair of side members 110 and 130.

What is claimed is: 
     
       1. A vehicle subframe to be attached to a vehicle body through a pair of front vehicle-body mounting portions provided opposite to each other in a width direction of the vehicle body on a forward side in a forward-rearward direction of the vehicle body, through a pair of rear vehicle-body mounting portions provided opposite to each other in the width direction on a rearward side in the forward-rearward direction, and through a pair of intermediate vehicle-body mounting portions provided opposite to each other in the width direction between the front vehicle-body mounting portions and the rear vehicle-body mounting portions in the forward-rearward direction, the vehicle subframe comprising:
 a pair of side members disposed opposite to each other in the width direction while extending in the forward-rearward direction, the pair of side members being provided with the pair of front vehicle-body mounting portions and the pair of rear vehicle-body mounting portions correspondingly, each of the side members being formed from a plate member; 
 a cross member extending in the width direction while connecting the pair of side members, the cross member being formed from a plate member; and 
 a pair of mounting members disposed opposite to each other in the width direction, each of which extends toward an outer side in the width direction while protruding toward an upward side in an upward-downward direction of the vehicle body, the pair of mounting members being provided with the pair of intermediate vehicle-body mounting portions correspondingly, 
 wherein the pair of side members includes upper side members and lower side members, respectively, the lower side members extending opposed on a downward side in the upward-downward direction to the upper side members while being elongated to the rearward side, and 
 the pair of mounting members is joined respectively to the lower side members of the pair of side members correspondingly, 
 and wherein the cross member includes an upper cross member and a lower cross member disposed on the downward side relative to the upper cross member and joined to the upper cross member, 
 the upper side members of the pair of side members are joined respectively to opposite outer front end portions of the upper cross member in the width direction, and extend from the opposite outer front end portions toward the forward side, and the lower side members of the pair of side members are joined respectively to the upper side members, the upper cross member, and the lower cross member, 
 the upper side members of the pair of side members are provided with the pair of front vehicle-body mounting portions correspondingly, while the lower side members of the pair of side members are provided with the pair of front vehicle-body mounting portions and the pair of rear vehicle-body mounting portions correspondingly, 
 the pair of side members respectively includes weakened portions on the forward side relative to the pair of intermediate vehicle-body mounting portions, the weakened portions being deformable against an impact force applied toward the rearward side, and 
 the lower side members of the pair of side members respectively include reinforcement portions continuously connecting the pair of intermediate vehicle-body mounting portions and the pair of rear vehicle-body mounting portions correspondingly in the forward-rearward direction, the reinforcement portions having a shape protruding in the upward direction or the downward direction in cross-section taken along a plane parallel to a plane defined by the upward-downward direction and the width direction. 
 
     
     
       2. The vehicle subframe according to  claim 1 , wherein the pair of mounting members is provided respectively with a part of a pair of arm support portions located opposite to each other in the width direction to support a pair of suspension arms correspondingly. 
     
     
       3. The vehicle subframe according to  claim 1 , wherein opposite end portions of the lower cross member in the width direction extend in the forward-rearward direction respectively along the reinforcement portions of the lower side members of the pair of side members, and constitute a pair of bulkhead portions, each of which extends toward the upward side, and
 upper end portions of the pair of bulkhead portions in the upward-downward direction are respectively joined to the upper cross member. 
 
     
     
       4. The vehicle subframe according to  claim 3 , wherein in cross-section taken along a plane parallel to a plane defined by the upward-downward direction and the width direction, the vehicle subframe has a closed cross-section defined by the upper cross member, the lower cross member, and the pair of bulkhead portions in cooperation with each other, a closed cross-section defined by the upper cross member, one of the lower side members of the pair of side members, and one of the pair of bulkhead portions in cooperation with each other, and a closed cross-section defined by the upper cross member, the other one of the lower side members of the pair of side members, and the other one of the pair of bulkhead portions in cooperation with each other.